Hi all,
I'm sure this has been resolved but I can't find a specific post on it.
I have DEM data as GeoTiffs, downloaded from the USGS website, imported and merged tiles in TG2 identically to the Ryan Archer tutorial demonstrates. I'm using a grid of 3x3 NED 1/3 arc seconds 0.25-degree tiles. Border is stitchable and border blending is set to 0.
If the terrain heightfield tiles are set to "flatten surface first" there is no problem and everything looks clean. If "flatten surface first" is unchecked, tiny spikes appear in both the 3dpreview and renderings. I've tried playing with all the settings I can find, including merging heightfields by mixing, highest, lowest, etc. If "flatten surface first" is unchecked, I cannot get rid of the spikes between tiles.
In an old post, I think Oshyan mentioned that with geo-referenced data you do not have to use "flatten first". Plus, with flatten first on, the edges of the vast terrain are raised in height, which I think is incorrect (please confirm). There is certainly a difference between the height of mountains in the distance with "flatten first" on versus it off. With flattening on, the mountains are raised way up (perhaps a hundred meters or more in this case) versus when flattening is off. Flattening on versus off will also have an effect on using altitude limits for color shaders.
So my questions are:
1) What is the accurate method (according to true-earth terrain) - flattening or non-flattening? If flattening is accurate, there's no problems and I retract this entire post.
2) If non-flattening is accurate, how do people get rid of the spikes between tiles? Or do users just use flattening and not worry about the accuracy of the terrain?
The closest posts I could find are old and I'm not using TER files:
http://www.planetside.co.uk/forums/index.php?topic=1232.0http://forums.planetside.co.uk/index.php?topic=1657.msg16313#msg16313http://forums.planetside.co.uk/index.php?topic=2036.msg20030#msg20030Thanks,
-Matt